On Sun, 18 Jan 2026 07:58:48 GMT, Alan Bateman <[email protected]> wrote:
> Are you 100% sure that AttachNotSupportedException make sense to throw in
> this configuration?
Yes.
We don't know whether target process provides a compatible `AttachProvider` if
Attach API could not access `/tmp` of target process. Target process might not
be Java. So I think it makes sence to throw `AttachNotSupportedException` with
the cause. The user get a hint from "Caused by" to check why Attach API failed.
[08:40:27] ~/d/e/jdk pull/28867 ❯
/home/slovdahl/dev/external/jdk/build/linux-x86_64-server-release/images/jdk/bin/jcmd
$(pgrep -f Reproducer.java) VM.version
52779:
com.sun.tools.attach.AttachNotSupportedException: Unable to access the
filesystem of the target process
at
jdk.attach/sun.tools.attach.VirtualMachineImpl.findTargetProcessTmpDirectory(VirtualMachineImpl.java:292)
at
jdk.attach/sun.tools.attach.VirtualMachineImpl.findSocketFile(VirtualMachineImpl.java:233)
at
jdk.attach/sun.tools.attach.VirtualMachineImpl.<init>(VirtualMachineImpl.java:84)
at
jdk.attach/sun.tools.attach.AttachProviderImpl.attachVirtualMachine(AttachProviderImpl.java:56)
at
jdk.attach/com.sun.tools.attach.VirtualMachine.attach(VirtualMachine.java:201)
at jdk.jcmd/sun.tools.jcmd.JCmd.executeCommandForPid(JCmd.java:113)
at jdk.jcmd/sun.tools.jcmd.JCmd.main(JCmd.java:97)
Caused by: java.nio.file.AccessDeniedException: /proc/52779/root/tmp
at
java.base/sun.nio.fs.UnixException.translateToIOException(UnixException.java:90)
at
java.base/sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:108)
at
java.base/sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:113)
at
java.base/sun.nio.fs.UnixFileSystemProvider.isSameFile(UnixFileSystemProvider.java:391)
at java.base/java.nio.file.Files.isSameFile(Files.java:1418)
at
jdk.attach/sun.tools.attach.VirtualMachineImpl.findTargetProcessTmpDirectory(VirtualMachineImpl.java:277)
... 6 more
-------------
PR Comment: https://git.openjdk.org/jdk/pull/28867#issuecomment-3765121718
